The present invention relates to an abnormal flow detecting circuit in a paper sheet counting machine, which is operable even if the kind of paper sheets is changed or the paper sheet delivery speed is changed because of a change of the load or the like. The abnormal flow detecting processing is subsequently automatically changed over to one suitable for the new kind of paper sheets or the new delivery speed.
There are various known paper sheet counting or money counting machines used for the bank business or the like and other various machines for counting voting cards and the like. Each of these known paper sheet counting machines is constructed so that paper sheets thrown into the counting machine are drawn out one by one by a paper sheet draw-out device and fed into a paper sheet delivery device. The number of paper sheets fed into the paper sheet delivery device is counted to determine the number of the paper sheets thrown into the counting machine. In such a paper sheet counting machine, it is very difficult to insure the separation of paper sheets one by one from the paper sheets thrown into the counting machine. Accordingly, in the conventional paper sheet counting machine, there is disposed on abnormal flow detecting circuit in the delivery passage through which a paper sheet is separated from and drawn out from the charged paper sheets travels or hopper. A passage detector is disposed to detect the passage time of the paper sheet, and the length or width of each paper sheet passing through the delivery passage is measured based on the result of detection of the passage detector. Thereafter, it is determined, based on the obtained length or width data, whether the paper sheet, the passage of which is detected by the passage detector, is a normal sheet or an assembly comprising two or more of sheets delivered together in the chain-like form or the like form. In such an abnormal flow detecting circuit disposed in the paper sheet counting machine, however, every time the kind of paper sheets to be thrown in the paper sheet counting machine is changed, it is necessary to change data of the reference length in a comparator for comparing the length data obtained based on the passage detection signal put out by the passage detector (the length of the period during which the passage detection signal is put out) with the predetermined reference length data (which is ordinarily set by a timer or the like).
In the conventional abnormal flow detecting circuit, the change of the reference length data to be supplied to the comparator is directly performed by an operator, and therefore, when the kind of paper sheets to be thrown in the paper sheet counting machine is changed, the operator makes many operations and it often happens that the charged paper sheets are not properly counted because of the operator's mistake in the input operation. Furthermore, it is necessary to perform a troublesome operation of measuring in advance the length of paper sheets to be thrown into the counting machine and obtaining necessary length data.
In the conventional paper sheet counting machine, if large quantities of paper sheets are charged in a hopper zone arranged in the counting machine, the load on the paper sheet draw-out device or paper delivery device is increased because of the weight of the paper sheets, and therefore, a slip is readily caused among rollers or pulleys or between the rollers or pulleys and belts trained thereon or the rotation speed of a motor for driving these rollers is reduced due to the increased weight. In such case, since the speed of delivery of paper sheets charged in the hopper zone of the paper sheet counting machine is gradually changed by the above-mentioned influences of the weight of the paper sheets, the length data obtained based on the length of the passage detection signal put out from the passage detector mounted on the delivery passage becomes inaccurate, with the result that the abnormal flow detecting circuit arranged in the paper sheet counting machine operates in an erroneous manner.